German Bundesliga club Bayern Munich's sporting director Matthias Sammer on Thursday said the suggestion of replacing winger Franck Ribery with Brazilian midfielder Douglas Costa is "disrespectful" to the former.

Bayern Munich completed their first big transfer of the off-season on Wednesday by signing Brazil international Douglas Costa from Ukraine side Shakhtar Donetsk for a reported 30 million euros ($33.3m).

France winger Franck Ribery is highly unlikely to recover from an ankle injury in time to feature for Bayern Munich in the Champions League fixture against Porto, coach Pep Guardiola said on the eve of the match on Monday.